WatchTime - August 2012

sition. After six hours the same tiles will be
in the center of the dial and form an hour
number. However, the tiles will be turned
180 degrees. In the same way, the entire
system is shifted by 180 degrees. For example:
the top left tile of the “11” (see photo)
will become the lower right tile of the
“5” after six hours – that is, its flip side,
which after another six hours will again be
the top left tile of the “11.” Within this period
the satellite will have moved four
times around the triangular gear and its arbor
will have turned 30 times along with
the tile.
The large wheel, which is driven by the
barrel, continues to advance 90 degrees
during an hour transition, in order to return
to the same place after four hours. Its
four satellite wheels will also be in the
same position after four hours, but not its
three additional satellites with their tiles.
They will move 120 degrees during each
transition, making one revolution around
the triangular gear after a three-hour period.
However, they do not return to the
same configuration they were in three
hours earlier. The tiles are now in a different
location in relation to one another. In
pairs, they alternately complete two or
three half turns every time they change position.
The triangular gear and the elliptical
gears are designed so that they can vary
these transmission ratios. This allows the
tiles to pass by one another without colliding
and to reappear in the center at the
proper time. After three hours, the same
satellite will again be in the center but
show the reverse side of the tile. Depending
on the tile, it will have turned seven or
eight times, 15 times in six hours, or 60
times a day.
The incredible calculation and design
work behind the hour-changing mechanism
of the Opus XI was only made possible
with computer programs that weren't
even designed a few years ago. Today
these programs can calculate, analyze,
draw and optimize the tooth shape of the
triangular and elliptical wheels and how
they mesh. The wheels themselves were
created through the use of photolithography
– a process where tiny components
can be manufactured with a precision
that cannot be achieved with conventional
manufacturing methods. The conical
Denis Giguet, the brains behind Opus XI
pinions for the bevel gears, for example,
are just 1.2 mm wide. Their shape, angles
and teeth are perfectly accurate thanks to
this new manufacturing technology. The
shape and path of each tile was also calculated
using computer technology in order
to minimize the space required for the
switching action. The case and sapphire
crystal, which themselves are the result of
complicated production processes, offer a
broad view of the astonishing hourly
movements. You may enjoy the exhilaration
of a wild carnival ride – with the
Opus XI it occurs once every hour.
As you might guess, Denis Giguet is
no newcomer to avant-garde horology.
Trained as an engineer, he served as head
of production for Harry Winston. In
2007 he launched his own brand, Manufacture
Contemporaine du Temps
(MCT), and designed its flagship watch,
the Sequential One – in which the hour
numerals are each composed of five
prism-like segments, arranged like slats in
a Venetian blind, which flip over to form
a new numeral at the appropriate time.
Twenty technical specialists worked with
Giguet to develop the Sequential One.
They included Eric Giroud and Jean-
François Mojon, who collaborated with
Harry Winston on, respectively, Opus IX
and X.
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